How can we add annotations in sequencediagrams? I want to add annotations (depicting some functionality) at the return of each response (on receiving ARes, BRes, CRes). How can I do that?
\documentclass[tikz]{standalone}
\usetikzlibrary{calc}
\usepackage{tikz}
\usepackage[underline=true]{pgf-umlsd}
\begin{document}
\begin{sequencediagram}
\newthread {r} {R} {}
\newinst [1] {a} {A}
\newinst [1] {e} {E}
\newinst [1] {u} {U}
\begin {sdblock} {Block} {}
\path (inst1.west) -- (inst4.east);
\begin{call}{r}{ACall}{a}{ARes}
\begin{call}{a}{B}{e}{BRes}
\begin{call}{e}{CCall}{u}{CRes}
\end{call}
\end{call}
\end{call}
\end {sdblock}
\end{sequencediagram}
\end{document}